1. Field of the Invention
The invention relates to electronic combination locks. More specifically, the invention relates to electronic combination locks in which an assembly of mechanical elements and computer-implemented processes provide a wide range of features.
2. Related Art
Various lock designs are known in the art. Conventionally, locks have been purely mechanical in design. However, with the development of reliable integrated circuits and microprocessors, more sophisticated and functional lock devices have become possible. However, even historically sophisticated electronic lock designs have failed to provide a number of desirable features.
Desirable features include the ability to be self-powered, so that correct operation of the lock is not prevented during power failures or battery failures. Whereas certain self-powered locks are known in the art, their designs suffer from the possibility that the self-charging function can interfere with the combination entry function.
Also, it is desirable that locks be tamper-evident and resistant to physical attack. Also, it is desirable to reduce the number of components in a lock, so as to enhance simplicity and promote reliability. Known locks have not adequately reduced the number of components, such as in the components used for bearing and retaining a combination dial, or in a mechanism used to act directly on the linkage to the bolt. Typically, known locks have involved gears which are unnecessarily complex and prone to failure.
It is also desirable to avoid a situation in which a user enters a correct combination, and thus enables the bolt to be withdrawn, but for some reason leaves the lock unattended so that some other unauthorized individual may open the lock. It is desirable to prevent an unauthorized person from opening the lock after the authorized person, who entered a correct combination, has departed.
Along a similar line, especially pertinent to self-powered locks which have a limited power storage capacity, it is desirable to ensure that there is sufficient energy to prevent any person from opening the lock if there is not enough power to operate the lock correctly. However, conventional locks have overlooked these features.
It is especially desirable in self-powered locks to use components which consume a minimum amount of power. Among the components of conventional locks which unnecessarily consume power are the sensors which sense motion and rotation of the combination dial. Conventional lock designs have overlooked a feature of reducing unnecessary power consumption in this area.
It is also desirable to provide a combination lock in which, after a person has entered a given number of combinations which are incorrect, it is made even more difficult for the user to open a lock. This feature is based on the premise that an unauthorized individual (or a rapid dialing machine) attempting to open the lock without knowing the correct combination will first enter several combinations incorrectly. However, conventional lock designs have not implemented this desirable feature that, based on an apparent attempt by an unauthorized user to open the lock, it should be made even more difficult for the user to open the lock.
Thus, conventional lock designers have overlooked many features, and combinations of features, which would provide a versatile, convenient, tamper-evident, reliable, power-efficient, electronic combination lock. It is to meet these demands that the present invention is directed.